The use of taped imbricated bags has been known for many years and the most commonly available form of these bags uses two separate adhesive carrier tapes which have an imbricated array of the bags placed on the tapes in such a way that the adhesive face of each tape contacts the exposed part of each bag in the imbricated array. Normally the lead bag of the array is attached to the tapes by its end at which the mouth is disposed.
U.S. Pat. No. 4,798,412 discloses a bag loader which includes a differential drive unit which drives two driving shafts onto which a cassette can be loaded. The cassette contains two tape winding spools one for each tape of a chain of bags. The differential drive unit of the bag loader can wind up the tapes onto the spools with equal tension. However, the drive unit of the bag loader is complicated and requires many components because of the two shafts which must extend from the bag loader with axes which are parallel but not coaxial. Furthermore, such a cassette is required to hold the spools in place and is necessarily quite large and bulky as the spools are positioned one beside the other to allow connection to the two shafts of the drive unit of the bag loader.
GB 2,064,477 discloses a bag loader which includes a differential drive unit which drives two tape winding spools which are positioned coaxially with one another. The differential drive gear is permanently attached to the bag loader (integral therewith). Thus, to load a succession of imbricated taped bags, the two used tapes need to be removed from the spools by an operator who also needs to connect the new tapes to the same empty spools in the bag loader.